What does a 30% discount mean?

That is, a discount of several tens of percent, for example, a 30% discount means a 30% discount, and a 15% discount means a 15% discount.

Then discount the original price, 70% is 0.7, 85% is 0.85, that is, remove the percentage and go back to two places.

So 30% off is the original price. Take 0.3 as an example, 100 yuan. 100 (original price) X 0.3=30 yuan (discounted price).